Question 1: Select all that apply
mediumAI-checkedSearch & PlanningBlocks world with STRIPS operators (AE = arm empty):
- Pickup(X): pre ontable(X), clear(X), AE
- Putdown(X): pre holding(X)
- Unstack(X, Y): pre on(X, Y), clear(X), AE
- Stack(X, Y): pre holding(X), clear(Y)
The initial state is ontable(A), ontable(C), on(D, A), on(B, C), clear(D), clear(B), AE. Which actions are applicable in it? Select all that apply.